Climatology may be defined as the mean value of a meteorological parameter over a given, ideally lengthy, time scale. The climatological winter temperature is therefore an average of winter temperatures over a large number of winters. Temperature observations for Bettles and Fairbanks in Alaska's interior show that winter temperatures are essentially bimodal. The climatology, or mean, of the two temperature modes is representative of neither mode. This has implications for the utility of medium range forecast models that use climatology as a significant input for simulations of temperature on the order of one week in advance.